Printing apparatus and printing control method

A printing apparatus for performing printing on a plurality of types of printing media including label paper having a plurality of labels arranged at an interval on elongated layout paper and a mark indicating a position of the label and being formed for each of the plurality of labels, the printing apparatus comprising:

• a transport unit configured to transport the printing medium in a transport direction;
• a printing head configured to perform printing on the printing medium at a predetermined position in the transport direction;
• a transmission-type optical sensor and a reflection-type optical sensor being arranged at positions upstream of the printing head in the transport direction, the transmission-type optical sensor being configured to detect, as a label position, a boundary between a region of the layout paper where the label is not arranged at the label paper and a region of the label, the reflection-type optical sensor being configured to detect the mark as a label position;
• and
• a control unit configured to execute:
• sensor determination processing for determining either of the transmission-type optical sensor or the reflection-type optical sensor as a sensor to be used for detecting a label position for positioning processing, the positioning processing corresponding to transport of the printing medium so that the label is positioned at a printing position of the printing head in the transport direction;
• and
• the positioning processing for each of the plurality of labels by controlling the transport unit based on a label position of each of the plurality of labels detected by the sensor determined in the sensor determination processing, wherein
• in the sensor determination processing, the control unit:
• causes each of the transmission-type optical sensor and the reflection-type optical sensor to detect a label position while causing the transport unit to transport the printing medium, and determines a sensor that succeeds in detecting a label position first as a first sensor and the other sensor as a second sensor;
• causes the transport unit to perform first transport for transporting the printing medium so that a first label position arrives at the printing position, the first label position being a label position detected by the first sensor;
• determines the first sensor as a sensor to be used for detecting a label position for the positioning processing when the first transport is terminated before the second sensor succeeds in detecting a label position during the first transport;
• and
• determines, as a sensor to be used for detecting a label position for the positioning processing, the first sensor or the second sensor that detects a position closer to the printing position among the first label position and a second label position that is a label position detected by the second sensor, when the second sensor succeeds in detecting a label position during the first transport.